JPH0640648A - Device for coating web during movement of paper or board - Google Patents

Abstract

PURPOSE: To prevent the excessive abrasion of a blocking element, by providing a coating chamber whose trailing side is defined each by a doctor element contacting the outside surface of a web being transferred and whose leading side by a resilient blocking element 6, and by adjusting the arrangement position of the blocking element. CONSTITUTION: This coating device, structured as a jet coating device, is provided with a reservoir mounted on a supporting beam and a jet duct 14 for supplying coating material to a coating chamber 9. Formed on a web material, the chamber 9 is defined each by a doctor element sliding by contacting the outside surface of a web W being transferred at its trailing side and by a resilient block element 6 at its leading side. The blocking element 6 comprises a strip spring supported by a supporting body 7, and inclined at a given angle along a bent edge 19. The angle 'a' formed by the free end edge and a tangent to a roll in the gap of the roll is set to 70 deg. to 110 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The invention relates to a coating device for a paper or cardboard web according to the preamble of claim 1.

[0002]

2. Description of the Related Art Such a device has already been disclosed in US Pat.
No. 688,516. First of this specification
According to the figure, a strip spring-shaped boundary element is adapted to wipe the web material. For this purpose
The boundary elements make a small angle of up to 32 °.

[0003]

However, this device is unsatisfactory because the paper or the boundary element itself is subject to considerable wear. In addition, the extra coating material
To be able to remain in the coating chamber, the structure of the entire device adjacent to the device must be very complex.

[0004]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent wear or abrasion of boundary elements on opposing rolls or webs, and to make the overall system relatively simple in design. Furthermore, a roll facing the boundary element,
Alternatively, when the gap with the web is relatively narrow, the flow rate of overflow through this gap is kept to a minimum while the damage at the beginning of the coating is minimized.

This object is achieved by the features of the characterizing part of claim 1.

[0006]

As the gauge pressure in the coating chamber increases, the free edge of the boundary element due to the particular construction of the boundary element, which is made of elastic material or is elastically held or elastically attached. And the size of the gap between the web and the roll increases quickly, which increases the flow rate of excess coating material through the gap from the coating chamber and prevents excessive gauge pressure in the coating chamber. It

In this regard, the angle between the boundary element (preferably strip spring-like) measured inside the chamber of coating material and the tangent to the adjacent web or roll is 95 ° and 70 °. Between 88 ° and 75 °. This means that as the pressure in the coating chamber increases, the boundary element immediately increases the size of the gap accordingly, which makes it particularly effective.

The boundary element is in the form of a very thin strip spring with a thickness of between 0.3 mm and 0.8 mm. As a result, significant damage or other damage to the web or roll that occurred at the beginning of coating is less likely to occur.
The boundary element can also be disengaged from it, for example, if a paper accumulation occurs adjacent to it, which can be caused by web tearing.

[0009]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Of course, the cross-sectioned parts are
All extend substantially along the axis of the roll and over the entire length of the roll relative to at least the full width of the paper or cardboard web. This of course means that both the bending lines described below in the boundary element, if designed as a continuous strip spring, or both the elastic component and the free edge of the boundary element and the roll W, or the gap between the running web. Is also true.

FIG. 1 shows a coating apparatus. This device is often referred to as a jet coating device and is usually provided with a jet duct 14 for supplying coating material to the coating chamber 9 in a reservoir which is attached to the support beam of the coating device.

This coating chamber 9 is formed on the web material and is on the trailing edge side (for the direction of movement of the web or roll casing W, see arrow P) on the moving web or on the outer surface of the roll. The front edge of the doctor 2 is bounded by the elastic border element 6. The doctor 2 in this example has a cylindrical bar-shaped measuring bar 3. This weighing bar 3
Preferably has a circumferential groove and is conventionally driven in the opposite direction to the web or roll.

This so-called roll doctor rod, namely the measuring bar 3, is held in a bed of synthetic resin,
Part of this bed is locked by the sheet-like holder 4 in the holding means of the main support beam 12 for the present coating apparatus. The metering bar 3 is pressed against the web or roll by a thrust element 5 (for example a pressure hose) which is only shown schematically. On the leading edge side, a gap s is provided between the free edge of the boundary element 6 and the web or roll W.

This doctor rod, namely the measuring bar 3
It should be noted that acts to remove excess coating material from the coating chamber 9, and a significant excess of coating material is required to satisfactorily coat the product. Weighing bar 3
A known blade can also be used as the blade.

In the present example, the elastic boundary element is composed of a strip spring and is formed along the bending edge 19 at a predetermined angle. The bending edge 19 is supported by a bar-shaped or plate-shaped support 7 so as to withstand the internal pressure in the coating chamber 9. In this example, this boundary element is clamped between the support 7 and the front wall 13 of the jet duct 14. Of course, other possible attachment means could be utilized.

The angle a between the free end of the boundary element and the tangent to the roll at the roll gap s, measured inside the coating chamber 9, is between 70 ° and 110 °, preferably Between 75 ° and 88 °. As a result, if the gauge pressure in the coating chamber 9 rises slightly, the boundary element moves outward, the gap s increases, and the gauge pressure in the coating chamber 9 decreases accordingly.

The gauge pressure in the coating chamber 9 is
Generally 0.02 to 0.5 bar. This gauge pressure is
It depends in part on the coating material (eg its amount).

Although the embodiment shown in FIG. 1 is the preferred embodiment, it will be appreciated that variations may be employed.
In FIG. 2, the demarcation element 6 ′ comprises two parts, a thin plate or strip 18 and a strip spring-like member 17 connected to this strip 18, which is shorter than in FIG. 1 and has a bending edge 19 ′. Made of.

It is also theoretically possible to form the part 18 'adjacent the roll in the boundary element as a relatively thick bar, as shown in FIG. In this example, the strip spring-like member 17 'must carry a relatively large weight. The purpose is to make the gap s as narrow as possible (maximum 2 mm, preferably about 1 mm) so that the strip spring-shaped boundary element is fairly thin, preferably between 0.3 mm and 0.8 mm thick. is there. This considerably reduces the risk of damage to the web or roll at the start of coating.

Advantageously, the essentially free edge of the strip-spring-shaped boundary element 6 is coated with a synthetic resin, for example polyurethane, polyethylene or rubber, so that it has a substantially circular cross section, as shown in FIG. is there.

In the present example, the coating component 21 can also abut the web material or the roll, ie be free of gaps.

FIG. 5 shows a variant with a strip-spring-shaped linear boundary element 6 '.

[0022]

The great advantage of the device according to the invention is that there is no lower limit on the size of the flexible boundary wall, the gap s, in the holding means during operation of the coating device, or in most cases with holding means. , It is not always necessary to displace. It need not be adjustable away from the web or closer to the roll. In any case, the fact that the gap is adjustable due to the flexibility of the boundary wall is another great advantage.

[Brief description of drawings]

FIG. 1 is a sectional view of a coating apparatus showing main features of the coating apparatus according to the present invention.

FIG. 2 shows another possible embodiment of a boundary element.

FIG. 3 shows another possible embodiment of a boundary element.

FIG. 4 shows another possible embodiment of a boundary element.

FIG. 5 shows another possible embodiment of a boundary element.

[Explanation of symbols]

2 Doctor 3 Weighing bar 4 Sheet holder 5 Thrust element 6, 6'Boundary element 7 Plate support 9 Coating chamber 12 Main support beam 13 Front wall 14 Jet duct 17 Strip spring member 18 Strip 19, 19 'Bending edge 21 Coated parts s Gap W roll

Claims (10)

[Claims] 1. Higher than ambient pressure, at least 0.01
A coating chamber (9) having a bar gauge pressure is provided, which coating chamber (9) is formed on a roll (W), the end of which on the trailing edge side with respect to the outer surface of the roll or web is a doctor. A device for coating a moving web of paper or cardboard, bounded by (2) and whose edge on the leading edge side with respect to the direction of movement of the surface is bounded by a bordering element (6). The boundary element (6) has a foil shape or a strip shape, at least a part of the boundary element (6) is movable, and the movable part is an elastic body or an elastic body. Mechanically attached plate or bar, the extension or chord (if curved) of the moveable part in its initial or design position passes through the intersection of this extension or chord with the roll. And tangent to the roll drawn to,
The movable part in the initial position is set so as to form an angle between 70 ° and 110 ° in the chamber, and a variable gap close to zero is provided between the movable part and the roll. The coating device is characterized by being formed. 2. A coating chamber (9) having a gauge pressure of at least 0.01 bar higher than the ambient pressure, said coating chamber (9) being formed on a roll (W), the outer surface of the roll or web. On the other hand, the end on the outlet side is bounded by the weighing bar (3), and the end on the inlet side with respect to the direction of movement is bounded by the border element (6). Device for coating the moving web of a boundary element in the form of a foil or strip, at least a part of which comprises an elastic body or an elastically mounted plate or bar. , The free edge of this plate or bar forms a narrow variable gap close to zero with the outer surface of the roll,
The coating device is characterized in that the gap constantly increases as the pressure in the chamber increases above the design pressure. 3. A tangent drawn in the gap (s) to at least a portion of the roll equal to the gap (s) measured in the coating chamber (s) or at least 30 mm adjacent to the free edge of the boundary element. , The angle between the boundary element is
3. The coating device according to claim 1, wherein the boundary element (6) is mounted so as to be between 75 ° and 88 °. 4. The boundary element (6 ') is a composite structure consisting of at least two parts, one of which (17) is a support.
A member elastically connected to (7) and the other member (8)
The coating apparatus according to any one of claims 1 to 3, wherein is a plate or bar having a relatively high rigidity. 5. One end of the boundary element (6 and 6 ') is clamped and has in its middle part a bending edge (19) (19') extending substantially parallel to the axis of the roll, A coating according to any one of the preceding claims, characterized in that it is supported between the clamping point and the bending edge (19) (19 ') to withstand the internal pressure of the coating chamber (9). apparatus. 6. Boundary element (6) (6 ') is characterized in that the length of the bending edge (19) (19') and the free edge measured towards the axis of the roll is between 20 mm and 100 mm, The coating apparatus according to any one of claims 1 to 5, characterized in that it is preferably between 20 mm and 100 mm. 7. The entire boundary element (6) is elastically constructed. 7. Coating device according to claim 6, characterized in that its thickness is constant, between 0.1 mm and 1.0 mm, preferably between 0.3 mm and 0.8 mm. 8. The internal pressure of the coating chamber (9) is 0.1.
Deflection of the edge of the boundary element (6) (6 ') in the vicinity of the roll or the web with each bar change is between 0.3 mm and 5 mm. The coating apparatus according to any one of claims. 9. A flexible boundary element (6) (6 ') (17) (18) (17') in, on, or with a support (7).
Coating according to any of the preceding claims, characterized in that (18 ') and (18') are not adjustable during operation so that they do not come close to or apart from the web or opposed rolls. apparatus. 10. A region according to claim 1, characterized in that some of the boundary elements are clamped or bent in a region that is flexible and the other is rigid. The coating device described.